Laser-based metrology systems may be used for large volume metrology, tracking and positioning. A known position sensor may be understood to be in the form of a cylindrical sensor as shown in FIG. 1. The cylindrical sensor may provide a nearly uniform response to laser light orthogonally incident to the cylindrical (vertical) axis, but such response may diminish and distort as the angle of incidence departs from orthogonal. In the limit, when the incident light is aligned with the cylindrical axis of the sensor, the sensor may be understood to be blind to the laser light. While the cylindrical position sensor may be understood to have a 360 degree field of view in the horizontal plane (around the vertical axis), the cylindrical position sensor may be understood to have only a field of view in a vertical plane of approximately ±60 degrees relative to the horizontal plane.
In addition to the above, the foregoing cylindrical sensor may be understood to contain electronic components within the cylindrical structure, which may be electromagnetically unshielded, thus prone to the negative effects of electromagnetic interference (EMI). EMI may be understood to add substantial noise to the output signal of the sensor.
What is needed is a position sensor which, among other features, may overcome the aforementioned limitations in the art of laser-based metrology systems.
Free-space optical communications has certain advantages over wireless radio-frequency (RF) methods, and also waveguide-based optical methods. Specifically, free-space optical communication has the potential for significantly greater bandwidth compared to wireless RF, and does not require a physical connection or medium as compared to waveguide (e.g., fiber-based) optical communication. However, an inherent limitation of free-space optical communication is the requirement for line-of-sight between the transmitter and the receiver, which is dependent on the reciprocal overlap of (optical) transmitter and receiver fields of view.
What is needed is a communication hub that can be used to transmit and/or receive laser signals from a wide range of angles. In addition, a communication hub that could create a multiplicity of separate channels to accommodate multiple bidirectional links would be advantageous for the parallel networking of multiple hub-linked devices.